927255 - Some heap-unclassified due to IPC strings(?)

Status: RESOLVED WONTFIX

(Core :: IPC, defect, P4)

Description

[Nicholas Nethercote [inactive]]

+++ This bug was initially created as a clone of Bug #919864 +++

Attachment 811297 [details] from bug 919864 shows 43 MiB of unreported strings, related somehow to IPC code.

I don't know where the memory allocated at that point ends up being stored, which is the information necessary to write a reporter for it.

Comment 1

[Andrew McCreight [:mccr8]]

My understanding was that they were being used as the backing store for blobs, or something.  So maybe one of the categories of blob things that aren't yet accounted for.

Comment 2

[Nicholas Nethercote [inactive]]

Hi Wander! The starting point for this bug is to see if it still happens. It seems like it's intermittent. Instructions for DMD are at https://wiki.mozilla.org/Performance/MemShrink/DMD. Please ask if you have any questions.

Comment 3

[Wander Lairson Costa]

Attachment: Compressed DMD full log for b2g process

The "interesting" log starts at line 345.

Comment 4

[Wander Lairson Costa]

Attachment: Uncompressed log only with IPC string log

Comment 5

[Wander Lairson Costa]

(In reply to Comment 2)

Hi Nicholas! It took more time than I was expecting but I could confirm the bug is still there. Attachment 8460557 [details] has full compressed logs, it is almost 80000 lines long, due to a lot of graphics related code reports. I am not sure if this is expected. The IPC string report starts at line 345. For convenience, Attachment 8460563 [details] contains an uncompressed log with only the IPC string report.

Comment 6

[Nicholas Nethercote [inactive]]

Full DMD logs tend to be pretty long, so that's expected :)

The IPC stuff is still there, but the size is much smaller than the one reported in comment 0 -- only 114 KiB instead of 43 MiB. It would still be nice to have a memory reporter for this memory so that it shows up in the memory reports, just in case it does occasionally get much larger. The tricky part with doing that is working out *where* this particular memory is stored -- I tried and failed when I looked at this a while ago.

https://wiki.mozilla.org/Memory_Reporting has some documentation on how to write a memory reporter. It would be also worthwhile to look at xpcom/base/nsIMemoryReporter.idl.

Comment 7

[Mike Lee [:mlee]]

Downgrading to P4 based on njn's comment 6:

(In reply to Nicholas Nethercote [:njn] from comment #6)
> 
> The IPC stuff is still there, but the size is much smaller than the one
> reported in comment 0 -- only 114 KiB instead of 43 MiB...
>

Comment 8

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

In both cases the memory is coming from DOM blobs.

Comment 9

[Wander Lairson Costa]

I thought the problem was when you take a screenshot, but it actually fires when you run the gallery app.

Comment 10

[Eric Rahm [:erahm]]

Moving to IPC, not sure if this is still necessary. It's possible we added reporters in the past 3 years.

Comment 11

[Sylvestre Ledru [:Sylvestre]]

No assignee, updating the status.

Comment 12

[Sylvestre Ledru [:Sylvestre]]

No assignee, updating the status.

Comment 13

[Nicholas Nethercote [inactive]]

No action in several years, closing.